Integration for feed dilution in oxidative dehydrogenation (odh) reactor system

Abstract

A system and method for producing ethylene, including dehydrogenating ethane to ethylene via an ODH catalyst in the presence of oxygen in an ODH reactor, discharging an effluent (including at least ethylene, water, and acetic acid) from the ODH reactor, recovering heat from the effluent for processing feed including ethane for the ODH reactor, recovering water from the effluent as recycle water for addition to the feed in performing water dilution of the feed, and adding oxygen to the feed to give a mixed feed including ethane, oxygen, and recycle water to the ODH reactor.

1 . A method of producing ethylene, comprising:
 adding water to ethane to give a mixture;   flowing the mixture through a feed heat exchanger to heat the mixture with effluent from an oxidative dehydrogenation (ODH) reactor;   adding oxygen to the mixture to give a mixed feed for the ODH reactor;   dehydrogenating the ethane to ethylene via an ODH catalyst in the presence of the oxygen in the ODH reactor; and   discharging the effluent from the ODH reactor, the effluent comprising ethylene, water, acetic acid, carbon dioxide, carbon monoxide, and unreacted ethane.   
     
     
         2 . The method of  claim 1 , comprising introducing the mixed feed to the ODH reactor, wherein the water added to the ethane comprises recycle water from processing of the effluent, and wherein the mixture upstream of the feed heat exchanger comprises ethane saturated with the water. 
     
     
         3 . The method of  claim 1 , wherein adding water to ethane comprises adding water to ethane in an ethane saturator tower. 
     
     
         4 . The method of  claim 3 , comprising heating in a cross-exchanger with the effluent the water added to the ethane before adding the water to the ethane in the ethane saturator tower. 
     
     
         5 . The method of  claim 3 , wherein adding water to ethane further comprises adding water to ethane in a conduit upstream of a heat exchanger upstream of the ethane saturator tower, and wherein the heat exchanger comprises a cross-exchanger that utilizes the effluent as a heating medium. 
     
     
         6 . The method of  claim 1 , wherein adding water to ethane comprises adding water to ethane in a conduit upstream of a heat exchanger, wherein the heat exchanger comprises a cross-exchanger that utilizes the effluent as a heating medium. 
     
     
         7 . The method of  claim 6 , comprising heating the water in a second cross-exchanger with the effluent before adding the water to the ethane in the conduit. 
     
     
         8 . The method of  claim 1 , wherein adding water to ethane comprises adding dilution steam from a dilution steam drum to a conduit conveying the ethane. 
     
     
         9 . The method of  claim 8 , comprising heating the water in a cross-exchanger with the effluent before introducing the water to the dilution steam drum. 
     
     
         10 . The method of  claim 8 , wherein adding water to ethane further comprises adding water to a conduit conveying the ethane upstream of a heat exchanger upstream of the ethane receiving the dilution steam, and wherein the heat exchanger comprises a cross-exchanger that utilizes the effluent as a heating medium. 
     
     
         11 . The method of  claim 1 , comprising adding water to the oxygen before adding the oxygen to the mixture, wherein adding the oxygen to the mixture comprises adding the oxygen to a conduit conveying the mixture. 
     
     
         12 . The method of  claim 11 , wherein adding water to the oxygen comprises adding water to a conduit conveying the oxygen upstream of a heat exchanger or adding the water to oxygen in an oxygen saturator tower, or a combination thereof, and wherein the heat exchanger comprises a cross-exchanger that utilizes the effluent as a heating medium. 
     
     
         13 . The method of  claim 11 , wherein adding water to the oxygen comprises adding dilution steam from a dilution steam drum to a conduit conveying the oxygen. 
     
     
         14 . (canceled) 
     
     
         15 . The method of  claim 1 , further comprising:
 separating the effluent in a flash drum into gas and raw acetic acid, wherein the gas comprises ethylene, water, acetic acid, ethane, carbon dioxide, and carbon monoxide, and wherein the raw acetic acid comprises acetic acid and water;   removing acetic acid and water from the gas in an acetic acid scrubber vessel;   utilizing a bottoms stream discharged from the acetic acid scrubber vessel as recycle water for diluting feed to the ODH reactor; and   heating the recycle water in a cross exchanger with the effluent.   
     
     
         16 - 18 . (canceled) 
     
     
         19 . An ethylene production system comprising:
 an oxidative dehydrogenation (ODH) reactor comprising an ODH catalyst to dehydrogenate ethane to ethylene and discharge an effluent comprising ethylene, water, acetic acid, carbon dioxide, carbon monoxide, and ethane;   a flash drum to separate effluent from the ODH reactor into gas and raw acetic acid, wherein the gas comprises ethylene, water, acetic acid, carbon dioxide, carbon monoxide, and ethane, and wherein the raw acetic acid comprises acetic acid and water; and   an acetic acid scrubber vessel to remove acetic acid and water from the gas and discharge a bottoms stream as recycle water for diluting feed to the ODH reactor, wherein the bottoms stream comprises water and acetic acid.   
     
     
         20 . The system of  claim 19 , comprising a cross exchanger to heat the recycle water with the effluent. 
     
     
         21 . The system of  claim 19 , comprising an ethane saturator tower to receive the recycle water and add the recycle water to ethane for feed to the ODH reactor. 
     
     
         22 . The system of  claim 21 , comprising a cross exchanger upstream of the ethane saturator tower to heat the recycle water with effluent before addition of the recycle water to the ethane in the ethane saturator tower. 
     
     
         23 . The system of  claim 21 , comprising:
 a cross exchanger upstream of the ethane saturator tower to heat a mixture of the recycle water and ethane with effluent; and   a conduit to convey the mixture as heated by the cross exchanger to the ethane saturator tower, wherein the ethane saturator tower receiving the recycle water comprises the ethane saturator tower receiving the mixture, and wherein the ethane saturator tower adding the recycle water to ethane comprises the ethane saturator tower adding the mixture to ethane in the ethane saturator tower received separately from the mixture.   
     
     
         24 . The system of  claim 19 , comprising a cross-exchanger to receive a mixture of the recycle water and ethane to heat the mixture with the effluent. 
     
     
         25 . The system of  claim 19 , comprising an oxygen saturator tower to receive the recycle water and add the recycle water to oxygen for feed to the ODH reactor. 
     
     
         26 . The system of  claim 19 , comprising a cross-exchanger to receive a mixture of the recycle water and oxygen to heat the mixture with the effluent for feed to the ODH reactor. 
     
     
         27 . The system of  claim 19 , comprising a steam dilution drum to receive and vaporize the recycle water to dilution steam for addition of the dilution steam to ethane or for addition of the dilution steam to oxygen, or a combination thereof, for feed to the ODH reactor. 
     
     
         28 . The system of  claim 27 , comprising a cross exchanger upstream of the steam dilution drum to heat the recycle water with effluent before introduction of the recycle water to the steam dilution drum. 
     
     
         29 . (canceled) 
     
     
         30 . The method of  claim 1 , further comprising:
 recovering heat from the effluent for processing mixed feed; and   recovering water from the effluent as recycle water for addition to the mixed feed, wherein recovering the heat reduces energy consumption in producing the ethylene, and wherein recovering the water reduces water consumption in producing the ethylene.   
     
     
         31 . The method of  claim 30 , wherein recovering heat from the effluent for processing the feed comprises heating the feed with heat from the effluent. 
     
     
         32 . The method of  claim 30 , wherein recovering heat from the effluent for processing the feed comprises heating the feed in a heat exchanger with the effluent as a heating medium. 
     
     
         33 . The method of  claim 30 , wherein recovering water from the effluent comprises condensing water and acetic acid in the effluent to give condensed water and condensed acetic acid, and separating raw acetic acid comprising the condensed water and the condensed acetic acid from the effluent to give a gas comprising ethylene, carbon dioxide, carbon monoxide, and unreacted ethane from the effluent. 
     
     
         34 . The method of  claim 33 , wherein recovering water from the effluent comprises processing the raw acetic acid to give acetic acid product and scrubbing water, wherein the scrubbing water is for an acetic acid scrubber that removes acetic acid from the gas, and wherein the recycle water comprises a bottoms stream discharged from the acetic acid scrubber. 
     
     
         35 . The method of  claim 30 , wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the ethane prior to adding the oxygen to the feed, or wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the oxygen prior to adding the oxygen to the feed, or a combination thereof. 
     
     
         36 . The method of  claim 30 , wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the ethane in an ethane saturator tower upstream of adding the oxygen to the feed, or wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the oxygen in an oxygen saturator tower prior to adding the oxygen to the feed, or a combination thereof. 
     
     
         37 . The method of  claim 30 , wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water as dilution steam to the ethane upstream of adding the oxygen to the feed, or wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water as dilution steam to the oxygen upstream of adding the oxygen to the feed, or a combination thereof. 
     
     
         38 . The method of  claim 30 , wherein adding the recycle water to the feed comprising ethane comprises vaporizing the recycle water in a steam dilution drum to give dilution steam for addition to the feed. 
     
     
         39 . The method of  claim 30 , wherein processing the feed comprises performing the water dilution of the feed. 
     
     
         40 . The method of  claim 39 , wherein recovering heat from the effluent for performing the water dilution comprises heating the recycle water with heat from the effluent. 
     
     
         41 . The method of  claim 39 , wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the ethane to give a mixture, and wherein recovering heat from the effluent for performing the water dilution comprises heating the mixture with heat from the effluent. 
     
     
         42 . The method of  claim 39 , wherein adding the recycle water to the feed comprising ethane comprises adding the recycle water to the oxygen to be added to the feed, and wherein recovering heat from the effluent for performing the water dilution comprises heating a mixture of the recycle water and the oxygen to be added to the feed with heat from the effluent. 
     
     
         43 . A method of producing ethylene, comprising:
 discharging an effluent from an oxidative dehydrogenation (ODH) reactor that dehydrogenates ethane to ethylene, the effluent comprising ethylene, water, acetic acid, carbon dioxide, carbon monoxide, and unreacted ethane;   performing water dilution of feed comprising ethane for the ODH reactor, wherein the water dilution comprises adding recycle water to the ethane;   recovering water from the effluent to give recovered water as the recycle water for performing the water dilution;   flowing the feed downstream of the water dilution through a feed heat exchanger to heat the feed with the effluent; and   adding oxygen to the feed to give the feed as a mixed feed for the ODH reactor.   
     
     
         44 . The method of  claim 43 , wherein performing the water dilution further comprises adding the recycle water to the oxygen. 
     
     
         45 . The method of  claim 43 , comprising recovering heat from the effluent for performing the water dilution. 
     
     
         46 . The method of  claim 45 , wherein recovering heat from the effluent for performing the water dilution comprises heating the recycle water in a heat exchanger with the effluent as a heating medium. 
     
     
         47 . The method of  claim 45 , wherein recovering heat from the effluent for performing the water dilution comprises heating a mixture of the ethane and the recycle water in a heat exchanger with the effluent as a heating medium, or heating a mixture of the oxygen and the recycle water in a heat exchanger with the effluent as a heating medium, or both.